Allow to specify the resistance of the attached shunt via DT by
adding the shunt-resistor property. Fall-back to the previous
default (1 mOhm) if unset.
Signed-off-by: Daniel Golle <daniel@xxxxxxxxxxxxxx>
---
v2: removed unneeded things and throw -EINVAL for shunt==0
drivers/hwmon/ltc4151.c | 21 +++++++++++++++++++--
1 file changed, 19 insertions(+), 2 deletions(-)
diff --git a/drivers/hwmon/ltc4151.c b/drivers/hwmon/ltc4151.c
index c86a184..419c6f7 100644
--- a/drivers/hwmon/ltc4151.c
+++ b/drivers/hwmon/ltc4151.c
@@ -30,6 +30,7 @@
#include <linux/kernel.h>
#include <linux/module.h>
+#include <linux/of.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/slab.h>
@@ -52,6 +53,7 @@ struct ltc4151_data {
struct mutex update_lock;
bool valid;
unsigned long last_updated; /* in jiffies */
+ unsigned int shunt; /* in micro ohms */
/* Registers */
u8 regs[6];
@@ -111,9 +113,9 @@ static int ltc4151_get_value(struct ltc4151_data *data, u8 reg)
case LTC4151_SENSE_H:
/*
* 20uV resolution. Convert to current as measured with
- * an 1 mOhm sense resistor, in mA.
+ * a given sense resistor, in mA.
*/
- val = val * 20;
+ val = val * 20 * 1000 / data->shunt;
break;
case LTC4151_VIN_H:
/* 25 mV per increment */
@@ -176,6 +178,7 @@ static int ltc4151_probe(struct i2c_client *client,
struct device *dev = &client->dev;
struct ltc4151_data *data;
struct device *hwmon_dev;
+ u32 shunt;
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
return -ENODEV;
@@ -184,6 +187,14 @@ static int ltc4151_probe(struct i2c_client *client,
if (!data)
return -ENOMEM;
+ if (of_property_read_u32(client->dev.of_node, "shunt-resistor", &shunt))
+ shunt = 1000; /* 1 mOhm if not set via DT */
+
+ if (shunt == 0)
+ return -EINVAL;
+
+ data->shunt = shunt;
+
data->client = client;
mutex_init(&data->update_lock);
@@ -199,10 +210,16 @@ static const struct i2c_device_id ltc4151_id[] = {
};
MODULE_DEVICE_TABLE(i2c, ltc4151_id);
+static const struct of_device_id ltc4151_match[] = {
+ { .compatible = "lltc,ltc4151" },
+ {},
+};
+
/* This is the driver that will be inserted */
static struct i2c_driver ltc4151_driver = {
.driver = {
.name = "ltc4151",
+ .of_match_table = of_match_ptr(ltc4151_match),
},
.probe = ltc4151_probe,
.id_table = ltc4151_id,
--
2.9.0
--
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